Specificity of experience dependent pitch representation in the brainstem
ABSTRACT Crosslanguage comparisons of brainstem-evoked potentials have revealed experience-dependent plasticity in pitch representation for curvilinear f0 contours representative of Mandarin tones. To assess the tolerance limits of this experience-dependent selectivity, we evaluated cross-linguistically (Chinese, English) the pitch strength and tracking accuracy of linear rising and falling f0 ramps representative of Mandarin tones 2 and 4. No crosslanguage differences in pitch strength or accuracy were observed for either tone, indicating that stimuli with linear rising/falling ramps elicit homogeneous pitch representations at the level of the brainstem regardless of language experience. We conclude that pitch extraction at the brainstem level is critically dependent on specific dimensions of pitch contours that native speakers have been exposed to in natural speech contexts.
Full-textDOI: · Available from: Ananthanarayan Krishnan, Sep 26, 2015
- SourceAvailable from: Gavin Bidelman
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- "Additionally , Chinese listeners' more salient CP for even non-speech stimuli further suggests an experience-dependent enhancement to the categorization of pitch that is domain-general but also influenced by long-term categorical representations and short/long-term memory garnered through tone-language experience (Xu et al., 2006a). Consistent with behavioral studies, neuroimaging work demonstrates that linguistic pitch experience tunes both subcortical (Bidelman et al., 2011a, 2011b; Krishnan et al., 2010; Xu et al., 2006b) and cortical (Chandrasekaran et al., 2007b; Gandour et al., 1998, 2000) encoding of pitch. Presumably, tone-languages not only enhance neural pitch representations , but also act to warp or restrict the perceptual space near category boundaries to supply a more dichotomous decision when classifying lexical tones (e.g., Bidelman and Alain, 2015; Bidelman et al., 2014b; Iverson et al., 2003). "
ABSTRACT: Categorical perception (CP) represents a fundamental process in converting continuous speech acoustics into invariant percepts. Using scalp-recorded event-related brain potentials (ERPs), we investigated how tone-language experience and stimulus context influence the CP for lexical tones-pitch patterns used by a majority of the world's languages to signal word meaning. Stimuli were vowel pairs overlaid with a high-level tone (T1) followed by a pitch continuum spanning between dipping (T3) and rising (T2) contours of the Mandarin tonal space. To vary context, T1 either preceded or followed the critical T2/T3 continuum. Behaviorally, native Chinese showed stronger CP as evident by their steeper, more dichotomous psychometric functions and faster identification of linguistic pitch patterns than native English-speaking controls. Stimulus context produced shifts in both groups' categorical boundary but was more exaggerated in native listeners. Analysis of source activity extracted from primary auditory cortex revealed overall stronger neural encoding of tone in Chinese compared to English, indicating experience-dependent plasticity in cortical pitch processing. More critically, "neurometric" functions derived from multidimensional scaling and clustering of source ERPs established: (i) early auditory cortical activity could accurately predict listeners' psychometric speech identification and contextual shifts in the perceptual boundary; (ii) neurometric profiles were organized more categorically in native speakers. Our data show that tone-language experience refines early auditory cortical brain representations so as to supply more faithful templates to neural mechanisms subserving pitch categorization. We infer that contextual influence on the CP for tones is determined by language experience and the frequency of pitch patterns as they occur in listeners' native lexicon. Copyright © 2015. Published by Elsevier Inc.NeuroImage 07/2015; 120. DOI:10.1016/j.neuroimage.2015.06.087 · 6.36 Impact Factor
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- "It is equally important to study how the potential reshaping of tone production by L2 learning relates to the perception of tonal differences, which presumably is also enhanced. Evidence for the specific effects of language experience on tone perception has been shown previously not only in behavioral research (Cooper & Wang, 2012; Francis, Ciocca, Ma, & Fenn, 2008; Lee, Vakoch, & Wurm, 1996; Wayland & Guion, 2004), but also in fMRI and ERP research (Chandrasekaran, Krishnan, & Gandour, 2007a; Chandrasekaran, Krishnan, & Gandour, 2007b; Chandrasekaran, Krishnan, & Gandour, 2009b; Kaan, Barkley, Bao, & Wayland, 2008; Krishnan, Xu, Gandour, & Cariani, 2005; Van Lancker & Fromkin, 1973; Wang et al., 2001, 2003; Wong & Perrachione, 2007; Xu, Krishnan, & Gandour, 2006). For instance, native Mandarin speakers outperformed native English speakers in discriminating between the Thai mid tone and low tone, suggesting that the perception ability gained by using one tone system may be transferable to a different tone system (Wayland & Guion, 2004). "
ABSTRACT: To perceive and produce Mandarin, adult second language (L2) learners need to learn to discriminate lexical pitch variations and develop the new sensorimotor skills needed to produce the lexical tones. In this paper, we investigated whether auditory discrimination and sensorimotor integration differ with Mandarin (tonal) language experience in the context of tonal language syllables and simple sustained vowels. We tested four distinct groups: native Mandarin speakers, Mandarin L2 adults, trained vocalists, and naïve adults (those with no tonal language exposure). Auditory discrimination was measured using two perceptual tasks, musical tone discrimination and Mandarin tone discrimination, the results of which were compared across the four groups. Group differences in sensorimotor integration related to lexical tone production were examined with a pitch-shift paradigm that assessed rapid motor responses to unexpected pitch perturbations. Mandarin speakers performed significantly better on Mandarin tone discrimination compared to the other three groups. Mandarin speakers also showed more attenuation of pitch-shift response amplitude (better vocal pitch control) during production of both the sustained vowel and Mandarin tones, especially compared to naïve speakers. These findings suggest that Mandarin speakers have more robust pitch control over self-produced vocalizations and are thus less affected by auditory feedback perturbations. This effect was particularly evident in response to the Mandarin high level lexical tone, for which the pitch-shift compensation patterns (with apparent attenuation in Mandarin speakers only) differed qualitatively from those of sustained vowels (with clear compensation in all groups), the rising tone (with apparent attenuation in all groups but naïve speakers), and the falling tone (with apparent attenuation in all groups). Trained vocalists also appear to rely more than naïve speakers on internal models when regulating voice F0 in the nonlinguistic domain (sustained vowel), but not in the linguistic domain (Mandarin tone). Native Mandarin speakers demonstrate robust internal models for lexical tone in both perception and production; this underscores the importance of developmental language experience but also provides evidence for the declination of the high level lexical tone which requires a mastery of tonal languages.Journal of Phonetics 01/2015; 51. DOI:10.1016/j.wocn.2014.12.003 · 1.41 Impact Factor
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- "The auditory brainstem response (ABR), a noninvasive objective measurement of brainstem integrity (Hall 1992; Hood 1998), is ideal for examining the biological mechanisms underlying improvements in hearing in noise because the response is stable from session to session even when recorded in the presence of an acoustic masker (Russo et al. 2005; Song, Nicol, et al. 2010a). This response, which is reflective of synchronized potentials produced by populations of neurons along the subcortical auditory pathway (Møller and Jannetta 1985; Chandrasekaran and Kraus 2010), can be elicited by a wide range of acoustic stimuli, including speech syllables (King et al. 2002; Krishnan 2002; Galbraith et al. 2004; Krishnan et al. 2004, 2005; Russo et al. 2004; Xu et al. 2006; Wong, Skoe, et al. 2007; Aiken and Picton 2008; Akhoun et al. 2008; Swaminathan et al. 2008). Brainstem synchronization is so precise that disparities on the order of tenths of milliseconds are clinically significant (Jacobson 1985; Hood 1998). "
ABSTRACT: We investigated training-related improvements in listening in noise and the biological mechanisms mediating these improvements. Training-related malleability was examined using a program that incorporates cognitively based listening exercises to improve speech-in-noise perception. Before and after training, auditory brainstem responses to a speech syllable were recorded in quiet and multitalker noise from adults who ranged in their speech-in-noise perceptual ability. Controls did not undergo training but were tested at intervals equivalent to the trained subjects. Trained subjects exhibited significant improvements in speech-in-noise perception that were retained 6 months later. Subcortical responses in noise demonstrated training-related enhancements in the encoding of pitch-related cues (the fundamental frequency and the second harmonic), particularly for the time-varying portion of the syllable that is most vulnerable to perceptual disruption (the formant transition region). Subjects with the largest strength of pitch encoding at pretest showed the greatest perceptual improvement. Controls exhibited neither neurophysiological nor perceptual changes. We provide the first demonstration that short-term training can improve the neural representation of cues important for speech-in-noise perception. These results implicate and delineate biological mechanisms contributing to learning success, and they provide a conceptual advance to our understanding of the kind of training experiences that can influence sensory processing in adulthood.Cerebral Cortex 07/2011; 22(5):1180-90. DOI:10.1093/cercor/bhr196 · 8.67 Impact Factor